1. Field of the Invention
The present invention relates to a fire alarm apparatus and, more particularly, to a fire alarm apparatus which detects accidental detachment of a fire detector by, e.g., burglary, and generates an alarm.
2. Description of the Prior Art
A fire alarm apparatus which detects burglary or the like of a fire detector and generates an alarm is disclosed in Japanese Patent Disclosures (Kokai) Nos. 52-151599 and 56-21294.
In the former apparatus, a contact mechanism is provided to short-circuit transmission lines when a fire detector body is detached from a socket, and in the latter apparatus, transmission lines are temporarily or periodically cut when a detector body is detached.
Conventional fire alarm apparatuses as described above pose several problems. After a fire detector is detached, the function of another detector connected to the same line is stopped. Alarm errors are generated by noise and the like because of the complex arrangement. A burglary alarm cannot be discriminated from a fire alarm or a disconnection alarm.